A Wisconsin welfare-reform program already lauded for improving the lives of welfare mothers also has been found to increase the likelihood that participants will marry.

Five years after never-married low-income mothers entered the New Hope Project in Milwaukee, 21 percent were married, compared with 12 percent of similar women in a control group, said study authors Hirokazu Yoshikawa and Anna Gassman-Pines, who presented their paper yesterday at the Society for Research in Child Development conference in Atlanta.

What made the difference in increasing marriage rates was that New Hope supplemented the incomes of the working mothers, said Mr. Yoshikawa, a psychology professor at New York University.

In other words, he said, it wasn’t enough for the women to have a stable job, they “needed to have more income.”

Unfortunately, he said, Congress is proposing welfare-related marriage-promotion policies that focus on relationship skills or marriage education, but “explicitly exclude poverty reduction as a route to increasing marriage.”

“Our study suggests that you should not ignore poverty reduction … as a route to increasing marriage rates among single mothers,” he said.

Work and marriage have been touted as modern anti-poverty approaches since the landmark 1996 welfare-reform law was enacted. Congress is working on its latest rewrite of the law and is likely to include both stronger work rules and new funding for pro-marriage activities.

The New Hope Project was implemented in the mid-1990s in two Milwaukee neighborhoods. More than 700 low-income parents — mostly welfare mothers — were randomly assigned to the program while another 600 were assigned to a control group that received regular state welfare services.

The New Hope parents worked 30 hours a week and received income supplements, health insurance and child-care subsidies from the New Hope program.

A 2003 study by MDRC, a nonpartisan social-policy research organization, found that, compared with the control group, New Hope parents had higher incomes, less poverty and more positive behaviors in their children.

Mr. Yoshikawa and Ms. Gassman-Pines studied a subset of New Hope’s mothers to see if the program also affected marriage rates.

They found that of 406 mothers who weren’t married when New Hope began, nearly 21 percent were married when the program ended five years later. Among women in the control group, 12 percent had married five years later.

Other studies of welfare reforms have shown little or no impact on marriage rates, but those other programs focused on increasing employment, not increasing incomes, Mr. Yoshikawa said.

The findings from New Hope are “robust … making us more confident that the program impact is not spurious,” he said, adding that more research is needed to explain both the connection between income and marriage and how a program such as New Hope affects couples’ relationships.